Process of manufacturing curved or rounded molds



UNITED STATES PATENT OFFICE.

WILLIAMH. GUILLEBAUD, OF HOBOKEN, NEW JERSEY.

PROCESS OF MANUFACTURING CURVED 0R ROUNDlED MOLDS, DIES, AND MATRICES.

SPECIFICATION forming part of Letters Patent No. 242,413, dated May 31, 1881.

Application filed January 25, 1881.

T 0 all whom it may concern:

Be it known that I, WILLIAM H. GUILLE- BAUD, a citizen of Switzerland, residing at Hoboken, in the county of Hudson and State of New J ersey,have invented new and useful Improvements in the Manufacture of Curved or Rounded Molds, Dies, or Matrices, of which the following is a specification.

This invention relates to the manufacture of curved or rounded molds dies, or matrices from a photo negative or positive or other transparent or translucent picture 5 and it consists in first obtaining a mold by actinic action of light upon a sensitized medium through a photo negative or positive orother transparent or translucent picture, then obtaininga plastic cast from such mold, and attaching the cast to a border-frame or backing at or near its edges, then modeling the cast in the desired manner, so that the cast is adapted to be electrotyped or stereotyped for the purpose of producing a working mold, die, or matrix, or adapted to other uses. It also consists in the plastic cast obtained by the foregoing process.

In carrying out my invention I proceed as follows, it beingunderstood, however, that the process may be varied in its details.

I first take a photo negative or positive, according to results desired, from the object or design to be represented in the working mold, die, or matrix. If this mold be desired for stamping or embossing, I take. the negative on ground glass, in order to obtain rounded slanting edges, which, especially in a deep mold, are the only proper edges for such work 5 or, instead of the negative, any other transparent or translucent picture may be used. Through said negative or picture, by actinic action of light upon a sensitized film of gelatine or other suitable medium, such as albumen, and in a known manner, I obtain a preliminary mold, and from this mold, alsoinaknown manner, a subsequent plaster cast, and from the latter a wax cast about one-sixteenth of an inch in thickness, other materials, however, being also adapted to the purpose of the wax.

Previous to taking thelareliminary mold the photographic picture may need to be retouched-that is to say, all the dark parts of the subject, which should by natural position be (No specimens.)

raised, I retouch so as to appear white; and all the light parts thereof, which should besunk, l retouch so as to appear dark, or vice versa.

The plastic (wax) cast obtained from the plaster cast is considerably smaller than the latter, because the wax or its substitute shrinks in cooling as much as one-eighth of an inch or more on a subject of five inches in length. Hence, when a plastic cast of exact size is wanted, it is necessary to ascertain exactly the shrinkage of the wax or its substitute on asurface the size of the cast, and to take the negative correspondingly larger, the plaster cast thus also becoming proportionately larger.

I now transfer onto a tablet of wood orother rigid material-say about three-sixteenths of an inch thick-an outline of the picture or subject, the exact size of the plastic cast-as, for example, by means of tracing-paper. I then out out the figure put on the tablet, as with a fine scroll-saw, keeping inside of the outline,

and thus obtain a rigid framecorrespondingto the edges of the plastic cast. I now heat this frame in a suitable manner and place the plastic cast upon it, face upward, in such a way that the edges of the cast are substantially parallel with those of the frame. I then press down the edges of the plastic cast, and when the frame cools the cast adheres firmly to it. I thus obtain aplastic cast the exact size of the picture bordered with a rigid frame, but left open or exposed on its back as well as on its face. The whole is then fastened to a stationary stand or table suitabl y constructed to leave the cast exposed both on its back and face, and the castis modeled in the desired manner.

It willbe seen that bythe arrangement of the plastic cast the artist now has the free use of both hands to model by pressure from the front or back, as may be required, to round up, depress, or curve upward or downward. He has the subject on which he works before him, and can in a short time model 'it to perfection. Its edges are kept firmly in place by the adhering frame, so that the pushing up or down to round up the figure does not affect them in any way, and does not alter the exact size of the cast, which is very important for embossing and other kinds of Work.

The back of the cast, which has now assumed a hollow form, may then be filled up flush with the face of the frame with plaster-of-paris or other suitable material to solidify the cast, theartiele being inverted for that purpose, so that when this filling has set or become hardened the cast can behandled without losing any of its relief, rounduess, or modulations. Hence it is capable of being electrotyped or stereotyped by known methods, thus yielding a mold or die or matrix in copper or other metal for embossing, stamping, or other work; or the cast may be used as a pattern for molding in sand to cast brass, silver, bronze, or other metal ornaments, which may be afterward finished by chasing, as usual.

What I claim as new, and desire to secure by Letters Patent, is-

The within-described process for making V. H. GUILLEBAUD.

Witnesses W. HAUFF, E. F. KASTENHUBER.

IL. s.] 

